The present invention relates to the technical field of blow moulding, and more specifically relates to a handle positioning apparatus outside mould for pre-inserted-handle bottle blow moulding machine, and a method of use thereof.
Polyethylene terephthalate (PET) bottles equipped with handles are not mainstream products in the market of packaging products, but they are necessary in the market of middle to high volume PET bottles. For example, they are quite commonly used for bottling cooking oil and sauces. Furthermore, PET bottles are gradually substituting traditional glass bottles due to a number of disadvantages existing in glass bottles, for example fragility, heavy weight, high energy consumption during the process of manufacturing and high transportation cost etc. Nowadays, there are mainly two methods for manufacturing PET bottles equipped with handles:
Pre-inserted-handle bottle: a bottle is blown by placing a handle and a preform tube into a bottle blow moulding machine at the same time. Since the handle and the bottle body are fixed tightly together, the handle has high resistance against tensional force and therefore is not easy to break off. However, the manufacturing of this kind of bottle requires high cost of labouring but the production efficiency is low. Although some but not many bottle blow moulding machines for making pre-inserted-handle bottle are equipped with mechanical arms for placing the handles into the moulds before bottle blow moulding, the use of mechanical arms as such does not result in high production efficiency. Besides, the cost of producing and installing mechanical arms is high.
Post-inserted-handle bottle: After blow moulding of the bottle body, a handle is combined with the bottle body to form the bottle. This kind of manufacturing method has high production efficiency and the cost of laboring is lower. However, the handle of this kind of bottle is not good at resisting tensional force, and the bottle itself is also not good at resisting pressure. Therefore this kind of bottle is not suitable for long distance transportation.
As shown above, the methods of manufacture directly affect product properties, production efficiency and the cost of production equipment. In these recent years, automatic bottle blow moulding machine for pre-inserted-handle bottle becomes a facility receiving major attention in facility research and development due to increasing market demand, rising cost of manpower resources and greater awareness of energy conservation and environmental friendliness. However, the problem of poor production efficiency has not been solved. In most of the existing prior arts of making pre-inserted-handle bottle, bottle blow moulding machines requiring manual operation are still used for manufacture. Problems associated with this kind of manually operated machines still exists, for example, high level of manpower input, unstable production quality, low production cost and unsafety etc. In some but not many cases, mechanical arms are used in the bottle blow moulding machines for making pre-inserted-handle bottle. An existing bottle blow moulding machine equipped with mechanical arms for making pre-inserted-handle bottle exemplified in FIG. 1 is used according to the following procedures:
1. According to FIG. 2-1, left and right mechanical arms is holding a handle, while a bottle is blown by using the bottle blow moulding machine;
2. According to FIG. 2-2, after the bottle blow moulding machine has finished blow moulding of the bottle and the mould has been opened, the bottle as produced is removed away from the mould with a safe distance.
3. According to FIG. 2-3, the mechanical arms enter the mould and put the handle in the mould.
4. According to FIG. 2-4, the mechanical arms retreat from the mould and return to a standby position.
5. According to FIG. 2-5, the bottle blow moulding machine closes the mould and blows the bottle. After that the mechanical arms hold another handle and then repeat step 1 again to start blow moulding of another bottle.
In the above procedures, the mould and the mechanical arms move according to the arrows shown in FIGS. 2-1 to 2-5.
The existing bottle blow moulding machine equipped with mechanical arms for making pre-inserted-handle bottle has the following disadvantages:
1. Long production cycle and low production efficiency: After blow moulding of a bottle, the bottle must be removed from the mould with a safe distance before the mechanical arms can enter the mould to place another handle therein, and the mould can only close again for blow moulding of the next bottle after the mechanical arms retreat away from the mould with a safe distance. This kind of operation wastes a lot of production time.
2. Maximum production capacity is twin mould production: Constrained by the movement of and the space required by the mechanical arms, the maximum production capacity for each production is limited to twin mould production. Therefore the production efficiency of the bottle blow moulding machine is limited.
3. High production equipment cost: Due to the use of mechanical arms, the equipment itself and its electrical control involve significantly increased cost. Furthermore, the limitation to the production efficiency of the bottle blow moulding machine will result in the need of purchasing a large quantity of this kind of machine in case of voluminous production. As such, the fixed cost of investment into the equipment will be too high compared to its valve, and thus reducing the willingness of investors to invest in this kind of equipment.